1. Technical Field
Embodiments relate to semiconductor systems and, more particularly, receivers and semiconductor systems including the same.
2. Related Art
Fast semiconductor systems are increasingly in demand with the improvement of their integration density. Synchronous devices operating in synchronization with external clock signals have been revealed to improve the operation speed thereof.
At first, single data rate (SDR) synchronous semiconductor devices have been proposed to improve the operation speed thereof. The SDR synchronous semiconductor devices may receive or output a single data through a single data pin for one cycle time of the external clock signal in synchronization with every rising edge of the external clock signal.
However, high performance devices operating at a higher speed than the SDR synchronous semiconductor devices have been demanded to meet the requirements of high performance semiconductor systems. Accordingly, double data rate (DDR) synchronous semiconductor devices have been proposed recently. The DDR synchronous semiconductor devices may receive or output the data in synchronization with every rising edge and every falling edge of the external clock signal. Thus, the DDR synchronous semiconductor devices may operate at a speed which is at least twice higher than that of the SDR synchronous semiconductor devices even without increase of a frequency of the external clock signal.